The present invention relates generally to packages for rolls of web material, particularly photographic film rolls, film packs, and other rolls of light sensitive material. The present invention is more particularly directed to a roll package which is protected from light and includes moisture barrier protection.
Rolls of light sensitive web material (such as paper and film) require light-tight packaging so that such rolls are not exposed to white or room light whereby the light sensitive characteristics of the rolls would be damaged. While such packaging must be light-tight, such packaging needs to facilitate the loading of the rolls in room light into cooperating apparatus which dispense or otherwise use the web material, such as a camera. Further, once positioned within the cooperating apparatus, the packaging must not adversely affect the operation of the roll during unwinding, and must not interfere with the roll if the web material is re-wound.
U.S. Pat. No. 5,655,659 (Kennedy), commonly assigned and incorporated herewith by reference, relates to a light-tight package for a roll of web material wherein an opaque leader portion is wound around the roll. End disks are attached to the end surfaces of the roll to form a light-tight package. While such a package has been suitable for its intended purpose, such packaging is not suited for a web material wound onto a spool having end flanges.
U.S. Pat. Nos. 1,454,812 (Jones), 1,454,813 (Jones), and 1,454,814 (Jones), all commonly assigned and incorporated herewith by reference, relate to a roll package wherein the web material is wound onto a spool having end flanges. As shown in FIG. 1, a spool 10 includes a core 12 and a pair of flanges 14,16 disposed at opposite ends of core 12. Web material W is wound between the flanges. An opaque leader 18 attached to web material W and wound about the web material to protect the web material from light.
Various packaging configurations have been developed to improve the protection of the web material from light. For example, as shown in FIG. 2, a roll package includes a leader 20 disposed at one end of the web material, and a trailer 22 disposed at the other end of the web material, with the trailer being attached to spool 10. Accordingly, when web material W is wound about spool 10 between end flanges 14,16, first the trailer is wound, then the web material is wound, with the leader being wound about the web material. Such a roll packaging configuration (i.e., trailer/web/leader) is available in a type of film package generally referred to as a 220 format film package.
In another roll packaging configuration, illustrated in FIG. 3 and generally referred to as a 120 format film package, a backing material 24 is disposed on one side of the web material along the entire length of the web material, with a length of backing material 24 being greater than the length of the web material. The backing material may be attached to one end of the web material. Accordingly, when the web material and backing material are wound onto the spool between the end flanges, the wound convolutions alternate between the web material and backing material.
In addition to protecting the web material from light, the roll packaging configuration must protect the web material from moisture since moisture may adversely affect the characteristics of the web material. U.S. Pat. No. 1,261,747 (McCurdy) relates to photographic film rolls wherein a light-excluding paper is water-proofed, the water-proofing agent being a derivative of cellulose such as nitro-cellulose or cellulose acetate. This relates to a water-proofed paper which sheds water, such as water droplets, but is not a significant barrier to the transmission of water vapor. That is, when tested, this water-proofed paper would have a high moisture vapor transmission rate.
U.S. Pat. No. 1,687,044 (Sulzer), commonly assigned and incorporated herein by reference, relates to a leader consisting of paper drawn through varnish. Like McCurdy, Sulzer varnished paper would have a high moisture vapor transmission rate.
Indeed, roll packaging taught by McCurdy and/or Sulzer has traditionally been packaged within a foil-laminate barrier pouch (i.e., bag) to ensure adequate protection against moisture vapor, as the moisture barrier properties of the water-proofed papers has been inadequate to restrict water vapor transmission.
While such packaging may have achieved certain degrees of success in their particular applications, a need continues to exist for an improved roll packaging configuration which would ensure protection from light, particularly during rugged handling/shipping conditions. The improved roll packaging configuration would also provide a low moisture vapor transmission rate.
An object of the present invention is to provide a roll package which protects a web material from light.
Another object of the invention is to provide such a roll package that has a low moisture vapor transmission rate.
Still another object of the invention is to provide such a roll package that is easily opened by a user.
Yet another object of the invention is to provide such a roll package that does not require additional packaging to provide adequate moisture vapor barrier protection.
These objects are given only by way of illustrative example. Thus, other desirable objectives and advantages inherently achieved by the disclosed invention may occur or become apparent to those skilled in the art. The invention is defined by the appended claims.
According to one aspect of the present invention, there is provided a roll package comprising a spool having a core and a flange disposed at opposite ends of the core; a length of web material wound about the core between the flanges; and a length of a protective material wound about the wound length of web material. The protective material has a moisture vapor transmission rate of less than about 0.1 grams per one hundred square inches for 24 hours when tested at 100 degree F., 100 percent relative humidity. In a particular embodiment, the protective material is a laminate having a first layer adhered to a second layer with the first layer being comprised of a compression rolled high density polyethylene and the second layer being comprised of a rubber-modified high density polyethylene. In a preferred embodiment, the first layer is comprised of a compressed, high density polyethylene, e.g., MONAX(copyright) PLUS, manufactured by Tredegar Industries.
According to another aspect of the present invention, there is provided a roll package comprising a spool having a core and a flange disposed at opposite ends of the core; a length of web material wound about the core between the flanges; and a length of a protective material wound about the wound length of web material. Each flange has an outwardly facing surface and an inwardly facing surface, the inwardly facing surface of each flange including a substantially planar portion adjacent an outer edge of the flange and a recessed portion inboard of the substantially planar portion. The protective material has a moisture vapor transmission rate of less than about 0.1 grams per one hundred square inches for 24 hours when tested at 100 degree F., 100 percent relative humidity.
The present invention provides a roll package which provides protection from light, and moisture barrier protection. In addition, the roll package of the present invention is readily opened by a user.